Put the lemon juice, zest, sugar and butter into a heatproof bowl.

Place the bowl over a pan of simmering water. make sure the bowl doesn't touch the bottom of the pan.

Stir occasionally over a gentle heat until the butter has melted.

Whisk the eggs and egg yolks together. If you think there may be egg shell or membrane in the mix, you can strain it as you add it to the lemon mixture, but it may not be necessary.

Whisk gently and constantly until the ingredients are all combined then continue to cook over a gentle heat, stirring all the time, until the mixture is thick enough to coat the back of a spoon. This should take about 10 - 15 minutes.

Remove from the heat and stir occasionally while the mixture cools.

Pour into sterilised jars, or you can simply leave the curd in the same bowl and refrigerate.